[linux-dvb] Re: Full featured card summary

[Holger Waechtler <holger@qanu.de>]

On Sunday 14 March 2004 23:22, Johannes Stezenbach wrote:
> Klaus Schmidinger wrote:
> > Johannes Stezenbach wrote:
> > > It doesn't make much sense to remove the power from the LNB
> > > while sending the DiSEqC sequence, but luckily vdr doesn't
> > > seem to do that ;-)  So, I guess that 'v' is a no-op.
> >
> > 'v'  means voltage low (13V)
> > 'V'  means voltage high (18V)
> >
> > So if there was no voltage before, 'v' will turn on the "low voltage".
>
> Right. I checked vdr source again, and now see how it works.
>
> I would think the frontend driver should power up the LNB upon open,
> and power it down after close.

The frontend or card driver driver should implement the internal FE_SLEEP 
ioctl and should switch off the LNB voltage there. If done properly this 
works properly with the shutdown timeout stuff.

> > > There are some mandatory delays before and after sending
> > > the DiSEqC sequence. The Nokia API rolled all that in a simple
> > > and convenient ioctl which would allow the driver to do
> > > all the timing (so that applications cannot fuck up), but Holger
> > > removed it.
> >
> > Why did he do that? Doesn't make any sense to me...?!
> >
> > Any chance we'll get that back - or do we have to live with the
> > fact that Holger has "f*cked up" the DiSEqC handling?
>
> Nokia specified the ioctl to run asynchronous, which causes
> some headaches for implementation. The current API also
> is more flexible and simpler, but forces every programmer
> to scrutinize the DiSEqC spec to use it right. The old
> API also made it difficult to integrate DiSEqC 2.0.
>
> For reference, the old API was in sec.h:
> http://linuxtv.org/cgi-bin/cvsweb.cgi/DVB/ost/include/ost/?hideattic=0#dirl
>ist

Maybe you want to check the little dvb-apps/test/diseqc.c test program, this 
one exercises all default DiSEqC commands and shows how to implement spec 
compliant DiSEqC communication using the frontend API.

Holger


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